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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 3120 | serge | 1 | |
| 2 | #define CLIP_BOTTOM 2 |
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| 3 | #define CLIP_RIGHT 4 |
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| 4 | #define CLIP_LEFT 8 |
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| 5 | |||
| 6 | |||
| 7 | { |
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| 8 | int xmin; |
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| 9 | int ymin; |
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| 10 | int xmax; |
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| 11 | int ymax; |
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| 12 | }clip_t; |
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| 13 | |||
| 14 | |||
| 15 | |||
| 16 | /*================================= |
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| 17 | |||
| 18 | |||
| 19 | { |
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| 20 | int flag; |
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| 21 | |||
| 22 | |||
| 23 | if( x < clip->xmin ) { |
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| 24 | flag |= CLIP_LEFT; |
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| 25 | } else if( x > clip->xmax ) { |
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| 26 | flag |= CLIP_RIGHT; |
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| 27 | } |
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| 28 | if( y < clip->ymin ) { |
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| 29 | flag |= CLIP_TOP; |
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| 30 | } else if( y > clip->ymax ) { |
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| 31 | flag |= CLIP_BOTTOM; |
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| 32 | } |
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| 33 | return( flag ); |
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| 34 | }; |
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| 35 | |||
| 36 | |||
| 37 | /*====================================================== |
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| 38 | |||
| 39 | |||
| 40 | { |
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| 41 | if( flag & CLIP_TOP ) { |
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| 42 | *y = clip->ymin; |
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| 43 | } else if( flag & CLIP_BOTTOM ) { |
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| 44 | *y = clip->ymax; |
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| 45 | } else if( flag & CLIP_RIGHT ) { |
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| 46 | *x = clip->xmax; |
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| 47 | } else if( flag & CLIP_LEFT ) { |
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| 48 | *x = clip->xmin; |
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| 49 | } |
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| 50 | } |
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| 51 | |||
| 52 | |||
| 53 | |||
| 54 | /*============================================================== |
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| 55 | |||
| 56 | |||
| 57 | active viewport based on the Cohen-Sutherland algorithm for line |
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| 58 | clipping. Return the clipped coordinates and a decision drawing |
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| 59 | flag ( 0 draw : 1 don't draw ). */ |
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| 60 | { |
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| 61 | int flag1; |
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| 62 | int flag2; |
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| 63 | |||
| 64 | |||
| 65 | flag2 = _L1OutCode( clip, *x2, *y2 ); |
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| 66 | for( ;; ) { |
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| 67 | if( flag1 & flag2 ) break; /* trivially outside */ |
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| 68 | if( flag1 == flag2 ) break; /* completely inside */ |
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| 69 | if( flag1 == 0 ) { |
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| 70 | block_inter( clip, x2, y2, flag2 ); |
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| 71 | flag2 = _L1OutCode( clip, *x2, *y2 ); |
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| 72 | } else { |
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| 73 | block_inter( clip, x1, y1, flag1 ); |
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| 74 | flag1 = _L1OutCode( clip, *x1, *y1 ); |
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| 75 | } |
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| 76 | } |
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| 77 | return( flag1 & flag2 ); |
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| 78 | } |
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| 79 | |||
| 80 | |||
| 81 | |||
| 82 | clip_t *src_clip,int *src_x, int *src_y, |
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| 83 | u32_t *w, u32_t *h) |
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| 84 | { |
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| 85 | int sx0, sy0, sx1, sy1; |
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| 86 | |||
| 87 | |||
| 88 | sy0 = *src_y; |
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| 89 | |||
| 90 | |||
| 91 | sy1 = sy0 + *h - 1; |
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| 92 | |||
| 93 | |||
| 94 | |||
| 95 | { |
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| 96 | int dx0, dy0, dx1, dy1; |
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| 97 | |||
| 98 | |||
| 99 | dy0 = *dst_y + sy0 - *src_y; |
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| 100 | |||
| 101 | |||
| 102 | dy1 = dy0 + sy1 - sy0; |
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| 103 | |||
| 104 | |||
| 105 | { |
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| 106 | *w = dx1 - dx0 + 1; |
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| 107 | *h = dy1 - dy0 + 1; |
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| 108 | |||
| 109 | |||
| 110 | *src_y += dy0 - *dst_y; |
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| 111 | |||
| 112 | |||
| 113 | *dst_y = dy0; |
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| 114 | |||
| 115 | |||
| 116 | }; |
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| 117 | } |
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| 118 | return 1; |
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| 119 | }; |
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| 120 |